P.Q.R.S.T. wave meanings
1. P Wave. What does this represent?
It represents the electrical activity of the heart's atria when the SA node is activated. The P wave is positive in most leads, which means it's above the baseline, or isoelectric line, on the ECG paper. It should also be rounded, not peaked, pointy or notched.
2. PR interval. What does this represent?
It represents the time taken for the electrical impulse to spread through the atria and down through the atrioventricular node, or AV node, to the heart's ventricular muscles. The PR interval on an ECG should measure 0.12 to 0.20 seconds, covering 3 to 5 small boxes on the ECG. If the PR interval is abnormally short or abnormally long, it may indicate a heart problem.
6. Explain the T-wave
T wave represents the repolarization, or recovery, of the ventricles. The interval from the beginning of the QRS complex to the apex of the T wave is referred to as the absolute refractory period. ... However, a negative T wave is normal in lead aVR The T wave on an ECG represents the repolarization, or recovery, of the ventricles. The T wave should not be greater than 5mm in the standard leads, or less than 10mm in the chest leads. The T wave occurs in the same direction as the QRS complex. It should be rounded, not pointed or asymmetrical. The shape of the T wave can indicate heart disorders
4. What is the QRS complex?
The QRS complex on an ECG represents the electrical activity associated with the activation of the heart's ventricles. In other words, it shows the depolarization of the ventricles. The Q Wave is the first negative deflection on the complex. The R wave is the first positive deflection of the complex. The S wave is the first negative deflection after the R wave. Can use the duration, amplitude, and shape of the QRS complex to diagnose cardiac arrhythmias, and other heart diseases
7. What is the QT interval?
The QT interval represents the time of ventricular activity including both depolarization and repolarization. It is measured from the beginning of the QRS complex to the end of the T wave. Normally, the QT interval is 0.36 to 0.44 seconds (9-11 boxes). The QT interval will vary with patient gender, age and heart rate.
5. What is the ST segment?
The ST segment is the flat, isoelectric section of the ECG between the end of the S wave (the J point) and the beginning of the T wave. ... The most important cause of ST segment abnormality (elevation or depression) is myocardial ischemia or infarction.
3. What is AV node function?
The atrioventricular (AV) node is a secondary pacemaker, and acts as a backup pacemaker to the sinoatrial node. It has an intrinsic rate of 40-60 beats per minute. The ventricular cells can also act as pacemakers, backing up the AV node. They have an intrinsic rate of only 20-45 beats per minute.
